Density profile, velocity anisotropy and line-of-sight external convergence of SLACS gravitational lenses

Understand

Data from 58 strong-lensing events surveyed by the Sloan Lens ACS Survey are used to estimate the projected galaxy mass inside their Einstein radii by two independent methods: stellar dynamics and strong gravitational lensing.

• We perform a joint analysis of these two estimates inside models with up to three degrees of freedom with respect to the lens density profile, stellar velocity anisotropy, and line-of-sight (LOS) external convergence, which incorporates the effect of the large-scale structure on strong lensing.
• A Bayesian analysis is employed to estimate the model parameters, evaluate their significance and compare models.
• We find that the data favor Jaffe's light profile over Hernquist's, but that any particular choice between these two does not change the qualitative conclusions with respect to the features of the system that we investigate.